1. Field of the Invention
This invention is concerned with highway trains of the kind in which a wheeled and steerable, motor-driven tractive vehicle having a rear portion is combined at least with a first load carrier having a forward end portion and a rearward end portion of which said forward end portion is rested on said rear portion of the tractive vehicle through the intermediary of a first pivot device capable of permitting horizontal angular displacement between said first load carrier and said tractive vehicle, an auxiliary vehicle having a front portion and a rear portion each of which is supported by at least one associated wheel axle having at least two wheels, said front portion of said auxiliary vehicle supporting said rearward end portion of said first load carrier through the intermediary of a second pivot device capable of permitting horizontal angular displacement between said auxiliary vehicle and said first load carrier, a second load carrier having a forward end portion and a rearward end portion of which said forward end portion is rested on said rear portion of said auxiliary vehicle through the intermediary of a third pivot device capable of permitting horizontal angular displacement between said second load carrier and said auxiliary vehicle, and an additional wheeled vehicle supporting said rearward end portion of said second load carrier, and in which all said vehicles and load carriers are separable from each other and said load carriers are interchangeable with one another.
If needed, such a highway train may be extended by making said additional wheeled vehicle generally similar to said auxiliary vehicle so that it will be able to support by its front portion said rearward end portion of said second load carrier though the intermediary of a fourth pivot device similar to said second one, by adding a third load carrier having a forward end portion and a rearward end portion of which said forward end portion may be rested on a rear portion of the additional wheeled vehicle thus designed through the intermediary of a fifth pivot device similar to said third one, and by also adding a further wheeled vehicle capable of supporting the rearward end portion of said third load carrier and bringing up the rear of the train, said third load carrier then being interchangeable with any one of said first and second load carriers although not necessarily being identical to any one of them.
Apparently a highway train of this kind may, whenever necessary, for instance when arriving at a station where only one of the load carriers is to be left for loading or unloading, be divided and reduced before continuing its journey to a further station. Also, if the train is supplemented with certain simple draw bars adapted to replace the load carriers as will be more closely described hereinafter, all its load carriers may be left at a desired station while only some, or all, of the supporting vehicles are transferred to another station for taking care of another group of load carriers.
2. Description of the Prior Art
In the past many different kinds of highway trains drawn by a tractive vehicle having a first pivot device, commonly known as a "fifth wheel" on its rear portion have been suggested. In most of these trains part of the total load is carried by a semitrailer having its forward end portion rested on the tractive vehicle and its rearward end portion supported by at least one fixed wheel axle, while the remainder of the load is carried by at least one ordinary trailer linked to the semitrailer through a draw bar and having at least one rear axle with fixed wheels and at least one front axle with steerable wheels following the direction of the draw bar. These trains, although extensively used, are unsatisfactory from many points of view, in particular because all the trailing vehicles have their own permanent wheel equipments which cannot be used for other transportation tasks when the frequently time-consuming loading and unloading of the cargo from the vehicles take place. In addition, these trains have a tendency to take a short cut when passing through sharp curves.
In other highway trains drawn by a tractive vehicle of the type already referred to certain load carriers having no wheel of their own and commonly in the form of shipping containers are provided with specially designed, separate supporting wheel axle units adapted to be connected to and disconnected from the lower sides of the load carriers in order to temporarily turn the latter into trailing vehicles which may be drawn in tandem in a certain order. In a typical train of this kind the first load carrier has its forward end portion rested on the tractive vehicle in semitrailer fashion and its rearward end portion supported by a four-wheeled undercarriage which is displaceable longitudinally of the load carrier between two operative and lockable positions in the rearmost one of which a "fifth wheel" on the undercarriage is exposed for receiving and supporting the forward end portion of a second load carrier also forming a kind of semitrailer by having attached under its rearward end portion a removable wheel axle unit. However, in all the trains of this class it is a fairly inconvenient and timeconsuming task to attach and remove the supporting wheel axle or undercarriage units from the load carriers, and also these trains behave objectionably on the road.
Further it has been suggested that in still another kind of highway train intended to be drawn by a tractive vehicle of the type referred to a pair of specially designed trailers each having at least two longitudinally movable supporting wheel axle units of their own with fixed wheels, i.e. wheels which cannot be turned for steering purposes, and each having both its forward and its rearward end portions adapted for connection to a "fifth wheel", such as the one on the tractive vehicle, are combined with an auxiliary vehicle having at least four fixed running wheels mounted on wheel axles which are displaceable longitudinally of the vehicle frame and in addition thereto two "fifth wheels", one on its front portion and another one on its rear portion. On the highway this train at its best and after several wheel axle displacements will be able to act as a combination of three semitrailers in tandem with the auxiliary vehicle forming the second one and having its forward end portion suspended from the rearward end portion of the first trailer. Such a train is not only complex and expensive but will behave poorly on the road and especially in sharp curves.